Frequency Mixer: 2 Inputs

Thread Starter

mauromj

Joined Oct 13, 2010
3
Good evening all,

I am working on a project that requires the mixing of 2 separate AC signals. I have done a lot of research and have not found any helpful information on how I can "add" these frequencies to produce a new frequency. For example, if I have an input1 of 5khz, and an input 2 of 1khz, I would (ideally) like an output of 6khz. I am not sure if this is possible or not. Even if this new output was not the sum, but simply the difference, multiplication, ect, I would be happy. Can someone please help as soon as possible?!

Thanks!
 

vk6zgo

Joined Jul 21, 2012
677
Good evening all,

I am working on a project that requires the mixing of 2 separate AC signals. I have done a lot of research and have not found any helpful information on how I can "add" these frequencies to produce a new frequency. For example, if I have an input1 of 5khz, and an input 2 of 1khz, I would (ideally) like an output of 6khz. I am not sure if this is possible or not. Even if this new output was not the sum, but simply the difference, multiplication, ect, I would be happy. Can someone please help as soon as possible?!

Thanks!
Google for "double balanced mixers".
These devices will give you quite a lot of cancellation of the input signals,but as 5kHz is quite close to 6kHz,you may still have a bit
of a battle trying to suppress the unwanted signal.
 

Thread Starter

mauromj

Joined Oct 13, 2010
3
Ok thank you! I will do some research on a double balanced mixer. I have some requirements however. I will need to build one of these, instead of using a premade chip. I have op amps, fets, bjt's that I will need implement. Hopefully I can find some info out there using these. If any of you find any good information, I would appreciate the help. Thanks
 

t06afre

Joined May 11, 2009
5,934
What you want to do is one of the core components in any lock-in amplifier. Here are some links
https://cpm.uncc.edu/sites/cpm.uncc.edu/files/media/tn1000.pdf
(note the appendix in this one)
https://cpm.uncc.edu/sites/cpm.uncc.edu/files/media/tn1001.pdf
https://cpm.uncc.edu/sites/cpm.uncc.edu/files/media/tn1002.pdf
https://cpm.uncc.edu/sites/cpm.uncc.edu/files/media/tn1003.pdf
There are many ways to do this. In your frequency range you can even use an analog multiplier IC. If you choose to use an analog approach. You should know that these most often do not work very well, then one of the input signals are very small compered to the other signal. What and why do you want to do this
 
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